¹Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia

Correspondence: Dr A Banerjee, The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3050, Australia. E-mail: banerjee@wehi.edu.au

Received 8 June 2007; Accepted 12 June 2007; Published online 17 July 2007.

Abstract

Toll-like receptor (TLR) signaling leads to the activation of mitogen-activated protein kinase and nuclear factor-B signaling pathways. While the upstream signaling events initiated at the level of adaptors and the activation of the downstream signaling pathways have received a lot of attention, our understanding of how these signaling pathways are coordinated to regulate gene expression is poorly understood. This review gives a selective overview on our current understanding of signaling downstream of TLRs, with an emphasis on how the upstream kinases like the mitogen-activated protein kinase kinase kinases (TAK1 and Tpl2) and inhibitor of -B kinase (IKK) coordinate the signaling events that steer the course of an immune response.